ORION: Clearing near-Earth space debris using a 20-kW, 530-nm, Earth-based, repetitively pulsed laser

Abstract

When a large piece of space debris forced a change of flight plan for a recent U.S. Space Shuttle mission, the concept that we are trashing space as well as Earth finally attained broad public awareness. Almost a million pieces of debris have been generated by 35 years of spaceflight, and now threaten long-term space missions. The most economical solution to this problem is to cause space debris items to reenter and burn up in the atmosphere. For safe handling of large objects, it is desired to do this on a precomputed trajectory. Due to the number, speed, and spacial distribution of the objects, a highly agile source of mechanical impulse, as well as a quantum leap in detection capability are required. For reasons we will discuss, we believe that the best means of accomplishing these goals is the system we propose here, which uses a ground-based laser system and active beam phase error correcting beam director to provide the impulse, together with a new, computer-intensive, very high-resolution optical detection system to locate objects as small as 1 cm at 500-km range. Illumination of the objects by the repetitively pulsed laser produces a laser-ablation jet that gives the impulse to de-orbit the object. A laser of just 20-kW average power and state-of-the-art detection capabilities could clear near-Earth space below 100-km altitude of all space debris larger than 1 cm but less massive than 100 kg in about 4 years, and all debris in the threatening 1-20-cm size range in about 2 years of continuous operation. The ORION laser would be sited near the Equator at a high altitude location (e.g., the Uhuru site on Kilimanjaro), minimizing turbulence correction, conversion by stimulated Raman scattering, and absorption of the 530-nm wavelength laser beam. ORION is a special case of Laser Impulse Space Propulsion (LISP), studied extensively by Los Alamos and others over the past 4 years.

Theoretical peak performance and optical constraints for the deflection of an S-type asteroid with a continuous wave laser

“…When plasma dominates the laser produced plume, increasing the laser intensity yields a reduction of the value of the coupling coefficient. According to Phipps et al (1996), in this regime, the dependence between the energy flux and the thrust coupling coefficient follows a power law of the form C m ∝ (Φλ √ τ ) −1/4 . In the last expression, τ is the pulse duration and λ the laser wavelength.…”

“…42 might give the impression that in the CW case ionization can occur at relatively low intensities. However, the model treated by Phipps et al (1996) assumes that absorption of the laser intensity by the plume is done in a time short enough that its 3-dimensional expansion can be neglected. In the case of interest both the expansion and absorption happen simultaneously.…”

Pulse-Laser Powered Orbital Launcher

“…The energy loss caused by beam diffraction is acceptable because the beam radius spreads to only 1.19 m at the transmission distance of 500 km, which is the typical value required for the launching system. The beam spread, attenuation, and refraction caused by nonlinear effects of the atmosphere, such as the variation of atmospheric refraction index, thermal blooming, Rayleigh, Raman and Mie scattering, have been analyzed for the ORION project (Phipps et al, 1996;Cambell, 1996), which is intended to remove debris on orbits using a pulse laser. Nonlinear effects are inferred to be negligible for transmission with a beam power density under a threshold determined by a laser pulse width and wavelength.…”

The Impact Imperative: Laser Ablation for Deflecting Asteroids, Meteoroids, and Comets from Impacting the Earth

“…Other applications can support the cost of a NEO-deflection laser system. These include capturing small asteroids and mining their rich rare-metal deposits [Blacic 1993] and deflecting Earth-orbiting space junk so that it burns up in the atmosphere [ORION concept : Phipps, et al 1996;Campbell 1996]. …”